How Many Alien Civilizations Exist Can Now Be Counted Using New Equation


Despite the fact that no one has ever proven the existence of alien life yet, a new study suggests that countless alien civilisations have already existed before us. The study published on April 22 in the journal Astrobiology takes into account the Drake equation, which calculates the chances how many alien civilisations are around by multiplying the number of habitable planets in the universe and the odds of a life forming on one of the planets.

It turns out that the chance of life being unique on Earth is only plausible if the chances are less than one in 10 billion trillion. However, even if there is only one chance in a trillion, this still implies that another intelligent life form could have already existed 10 billion times over the universe’s history.

In the Milky Way alone, that chance is as little as one in 60 billion. Nevertheless, the researchers admit that if aliens existed, they are most likely extinct.


In 1961, astrophysicist Frank Drake developed an equation to estimate the number of advanced civilizations likely to exist in the Milky Way galaxy. Credit: University of Rochester

The researchers believe that other civilisations only evolved for as long as humans have been around. This means that all alien civilisations have only lasted for 10,000 years.

Even if they weren’t extinct, communicating with them is still impossible. If they are 20,000 light years away from us, relaying messages with them back and forth would take at least 40,000 years.

The researchers believe that the findings have implications on how to save the planet from exacerbating climate change. Analysing possibly habitable planets across the universe can tell us how alien civilisations coped with their planet’s climate conditions.

“Our results imply that our evolution has not been unique and has probably happened many times before,” says co-author Adam Frank, professor of physics and astronomy at the University of Rochester. “The other cases are likely to include many energy intensive civilisations dealing with their feedbacks onto their planets as their civilisations grow. That means we can begin exploring the problem using simulations to get a sense of what leads to long-lived civilisations and what doesn’t.”


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